ZURICH (Reuters) - UBS's (UBSG.VX) chairman said a default by Greece is seen by the International Monetary Fund as "systemically controllable" and he believed it would have a negligible impact on the Swiss bank itself, according to a newspaper interview published on Saturday.

Athens is lurching closer to bankruptcy, with its next big test on May 12, when it is due to pay 750 million euros to the IMF. Euro zone finance ministers told Greece on Friday that its leftist government would get no more aid until it agreed a complete economic reform plan.